This project is a critical part of an overall research program aimed at developing a precise understanding of the detailed mechanism of cell growth in fungal hyphae. To date, the only technique that has proven suitable for experimentally, locally, and nondestructively manipulating the size, rate, direction, and shape of growing fungal hyphae is the use of infared (820 nm) laser microbeams to position and move the organellar complex and individual organelles which mediate cell growth. These cell components contribute membrane and cell wall materials to expand the surface of the hyphal tips in precise localized regions of the cell and along a gradient which causes a hyphal tip to assume a characteristic shape. We can control the subtleties of cell morphogenesis at will by moving and repositioning organelles either by trapping or "chasing", them with a laser so that they are transported to predetermined sites in the cell.